Re: [RFC][PATCH] Prevent overriding of Symbols in the Kernel,avoiding Undefined behaviour

[Rusty Russell]

On Wed, 2005-12-14 at 20:40 -0800, Andrew Morton wrote:
> Ashutosh Naik <ashutosh.naik@xxxxxxxxx> wrote:
> >
> > This patch ensures that an exported symbol  does not already exist in
> >  the kernel or in some other module's exported symbol table. This is
> >  done by checking the symbol tables for the exported symbol at the time
> >  of loading the module. Currently this is done after the relocation of
> >  the symbol.
> 
> This patch causes weird things to happen on ppc64.

And probably in general:

+       for (i = 0; i < mod->num_syms; i++)
+               if (!__find_symbol(mod->syms[i].name, &owner, &crc, 1)) {
+                       name = mod->syms[i].name;
+                       ret = -ENOEXEC;
+                       goto dup;

__find_symbol returns the value, or 0 on failure.  This test is
backwards, as is the one below it.

Rusty.
-- 
 ccontrol: http://ozlabs.org/~rusty/ccontrol

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